Revisiting the ESA model: a historical test

The energy–stability–area (ESA) model put forth by Lowery and Gray (Am J Polit Sci 39(1):1–29, 1995) focused scholarly attention on two factors critical to interest group mobilization: the density and diversity of groups within a population. Since that seminal publication, researchers have continued to refine the model and its applications. Yet, so far, these studies have been focused on modern interest groups. Here, we extend Lowery and Gray’s (1995) cross-sectional ESA model by studying the strength of state branches of three interest groups—the Woman’s Christian Temperance Union, the Patrons of Husbandry (Grange), and the Grand Army of the Republic—in the mid-1910s. We find some support for the ESA model across all three groups, though density dependence, a key part of the Lowery and Gray story (1995), is not significant in our historical models. Our results further deviate from Lowery and Gray’s work by finding strong evidence for the role of government size on interest group mobilization. Ultimately, we conclude that the ESA model provides important insights on the development of membership associations during the early twentieth century, albeit with some important amendments for the period.